1. Field of the Invention
The present invention relates to an audio signal processing apparatus, an audio signal processing method, and a program for deriving output audio signals with desired directivity from two-channel input audio signals.
2. Description of the Related Art
A passive matrix method is widely used to separate a center sound to be localized at the center in front of the listener and a so-called surround sound from two-channel input audio signals, such as a left channel input audio signal L and a right channel input audio signal R. The passive matrix method involves generating a sum L+R and difference L−R of the left and right channel input audio signals in a simple manner. The sum L+R is separated as a center sound and the difference L−R is separated as a surround sound.
As a method for improving the degree of separation of separated signals, PCT Japanese Translation Patent Publication No. 2003-516069 discloses an active matrix method for suppressing crosstalk components included in separated signals, and particularly refers to a technique for adaptively control crosstalk by applying feedback control.